Field of the Invention
The invention relates to a method and an energy-carrier production installation for carbon-dioxide-neutral compensation of current level fluctuations in a power supply system as a result of generation peaks and generation troughs in the generation of electrical energy, in particular from regenerative energy sources. In particular, the invention relates to the generation of electrical energy by conversion of wind energy, solar energy, geothermal heat, by utilizing biomass, and/or tidal forces.
Description of Related Art
Considering the increasing scarcity of fossil fuels in the long term and the threat of global warming caused by green house gases, development and exploitation of renewable regenerative energy sources such as wind and solar energy, but also geothermal heat and tidal power as alternatives or parallel to conventional energy generation from fossil energy carriers becomes increasingly important.
One drawback in using regenerative energy sources for the generation of electrical energy is the fact that the natural supply situation is difficult to predict and is influenced by natural fluctuations. So for instance, depending on changes caused by the weather, time of the day or season, generation peaks or generation troughs of the electrical energy generated from regenerative energy sources occur. Fluctuating electricity generation in particular caused by instable weather conditions, times of the day or seasonal influences is faced by a non constant electricity demand from the consumer.
When electricity generated from regenerative energy sources is fed into an electrical power supply system, generation peaks and generation troughs can cause major problems. Adaptation of power plant technology to such fluctuating current levels involves considerable efforts.
For instance, there are uncertainties in the generation of electricity by using wind power, which are caused by unpredictable weather conditions, wherein in periods of wind calm conventional power plants are operated at peak load during peak demand hours while in periods, when sufficient wind is available for the generation of electricity, the demand for energy can be so low. As such, the power plant has to be operated below its capacity and, thus, causes higher carbon dioxide emissions. Moreover, when the operator of a wind power station is not able to feed the power into the power grid because of a potentially dangerous grid overload, the wind power plant has to be shut down, thus reducing the operating profitability of the same.
Thus, in the field of utilization of regenerative energy sources for the generation of electrical energy there is a need for a cost-effective and efficient method in order to be able to compensate generation peaks and generation troughs.
From prior art, a method is known for breaking down water into hydrogen and oxygen by means of electrolysis. But storing hydrogen is a complicated and costly process. Moreover, the transport of hydrogen to the place of its actual use requires a hydrogen infrastructure, which is usually not in place. Another disadvantage is the fact that oxygen released during electrolysis is used in limited ways only. Thus, prior art provides a method for conversion of carbon dioxide and hydrogen into an energy-carrier, which contains hydrocarbon, by using catalysts such as methanol and methane. Methods for providing storable and transportable carbon-based energy carriers by using carbon dioxide as carbon source and by using electrical energy are disclosed in International Patent Application Publication No. WO 2010/069622 A1. In addition, the catalytic production of methanol is also disclosed in International Patent Application Publication No. WO 2010/069385 A1 and in International Patent Application Publication No. WO 2010/069685 A1.